High speed wet spinning technique

ABSTRACT

In the spinning process the filaments leaving the spinnaret in a vertically downward direction pass through a first coagulating bath and the fluid entrained by the filaments is decelerated by means of concentric angularly directed jets of fluid prior to passage through a second coagulating bath. The filament may then pass-over a bar which changes the direction of the filament and removes entrained fluid. Further coagulating bath treatment may be provided by passage through the trough of a saddle guide prior to passage between a pair of vane type rolls for shaking the remaining bath fluid from the filaments. The filaments are then loosely deposited on a travelling web for further treatment. Specific apparatus for carrying out the process is provided including elastic covered vanes on the rolls as well as several embodiments for the decelerating fluid jet arrangement.

United States Patent [191 Miyazaki et a1.

[ HIGH SPEED WET SPINNING TECHNIQUE [73] Assignee: Asahi Kasei KogyoKabushiki Kaisha, Osaka, Japan [22] Filed: June 28, 1972 [21] Appl. No.:266,965

Related U.S. Application Data [62] Division of Ser. No. 94,468, Dec. 2,1970, Pat. No.

[30] Foreign Application Priority Data Dec. 2, 1969 Japan 44/96347 Dec.2, 1969 Japan 44/96348 [52] U.S. Cl. 425/445, 425/336, 19/66 T, 425/86[51] Int. Cl. B29f 3/00 [58] Field of Search 19/65 T, 66 T;

[56] References Cited UNITED STATES PATENTS 2,027,911 l/l936 Hofmann264/199 X Primary Examiner'R. Spencer Annear Attorney-Sughrue, Rothwell,Mion, Zinn and Macpeak [5 7 ABSTRACT In the spinning process thefilaments leaving the spinnaret in a vertically downward direction passthrough a first coagulating bath and the fluid entrained by thefilaments is decelerated by means of concentric angularly directed jetsof fluid prior to passage through a second coagulating bath. Thefilament may then passover a bar which changes the direction of thefilament and removes entrained fluid. Further coagulating bath treatmentmay be provided by passage through the trough of a saddle guide prior topassage between a pair of vane type rolls for shaking the remaining bathfluid from the filaments. The filaments are then loosely deposited on atravelling web for further treatment. Specific apparatus for carryingout the process is provided including elastic covered vanes on the rollsas well as several embodiments for the decelerating fluid jetarrangement.

1 Claim, 20 Drawing Figures PATENIEDDEI 16 I975 3.765818 SHEEI 2 OF 6FIG. l9 FIG. 20

PuBLmA rTON Eq b. "5/56 5%? 2275 5 c o G PATENTEDUEI '18 1975 SHEET 3 BF6 PATENTEDUET 16 ms 3.765818 SHEET 60F 6 FIG. I?

5 l6- 3 l4- rl2- p- IO- 5 2 3 I 4 l l l J l L ,MM FIG. I8 22 FILAMENTTENSION, G 4 o: co 5 R 3 5 I l I I I 200 400 600 800 IObO- HIGH SPEEDWET SPINNING TECHNIQUE This is a division of application Ser. No.94,468, filed Dec. 2, 1970, now US. Pat. No. 3,689,620.

This invention relates to a high speed wet spinning technique.

Conventional wet spinning type filaments manufacturing processes andapparatuses are defective on account of unacceptable number of brokenfilaments and a considerable generating rate of mass flufis appearing inthe spinning and the like stages appearing in the after-processingstages when the whole operational speed of the manufacturing plantshould be increased to as high as 400 m per min. or stll higher.

According to our experimental knowledge, this drawback is caused byimpinging of the entrained bath liquid by the extruded and coagulatingfilaments into a secondary bath pool, which leads to a disturbance ofthe pool and unfavourable filaments quality.

The main object of the invention is to provide a process and method foreliminating such liquid disturbance in the secondary bath pool providedin each of the spinning and coagulating unit of the filamentsmanufacturing plant.

Secondary grave drawback as frequently met in the continuous wet-spunfilaments are the difficulty in the provision of filamentstate-converter which serves for transforming the tensioned state of thefilaments in the spinning and coagulating stage of the filaments to beafter-treated in various successively carried-out stages.

The second object is to provide a process and apparatus adapted forworking in an efficient way for the above purpose.

In the wet spinning process and apparatus, use of stationary filamentsguide(s) is unavoidable. When, operating the wet-spun filamentmanufacturing plant at a high speed such as 400 in per min. of stillhigher, the contact of the filaments with such guide means, naturally ofrigid construction, will provide filament breakages at a substantial andthus unacceptable rate.

In the case of the manufacture of cuprammonium filaments, as an examplesuch filaments guide means as pins or combs, which are kept incontinuous and mechanical contact with the extruded and coagulatingfilaments are subjected to a gradually increasing deposit of copperhydroxide which will become harder copper oxide. This hard oxidedeposit, when accumulated on the contacting surface(s) of the guide pinsand/or combs, will bring filament breakages which are increased more andmore as the plant operational speed is accelerated. When a filament isbroken by such mechanical contact thereof with the hard and irregularsurface of the deposited copper oxide, it entangles around neighboringfilament(s), thus increasing the number of filaments as themanufacturing or aftertreating steps are passed by the group of thewet-spun and coagulated filaments.

According to the present invention, the entrained coagulating bathliquid by the travelling filaments is hemmed in its velocity by use of aunique liquid brake.

According further to the novel teaching of the invention, theafter-treatments of the spun and coagulated filaments are performed in aperfectly loosed state for abolishing the conventional pins and combsconventionally used in the after-treating stages and, indeed, by use ofa unique and efficient filaments state convention step and means fortransforming the tensioned state of the filaments into a perfectlyloosened state thereof in the after-treating stages.

These and further objects, features and advantages of the invention willbecome more apparent when read the following detailed description of theinvention by reference to the accompanying drawings, in which:

FIG. 1 is a representative embodiment of the continuous man-madefilaments based on the wet spinning process and embodying the principlesof the present invention, the whole representation being shown dividedlyfor reason of drawing space in two sections which should be conjointedby overlapping the section lines X-X.

FIG. 2 is an enlarged axial section of a spinning assembly employed inthe manufacturing plant shown in FIG. 1.

FIG. 3 is an enlarged axial section of a liquid-braking and sprayingunit employed in the plant shown in FIG.

FIG. 4 is an enlarged perspective view of a saddle type filaments guideemployed in the plant shown in FIG. 1.

FIG. 5 is an enlarged elevational view of a pair of filaments-shake offrolls employed in the same plant.

FIG. 6 is an enlarged perspective view of a part of said roll for theillustration of an elastic sheath attached to each of the vanes of saidroll.

FIG. 7 is a schematic view of the spinning and coagulating unit,especially showing the relative axial dimensions of its mainconstituting parts.

FIG. 8 is a schematic longitudinal section of the inner funnel employedin the plant shown in FIG. 1, especially illustrating main dimentionalrelationship.

FIG. 9 is a schematic longitudinal section of the unit shown in FIG. 3,especially showing the main relative dimensions thereof.

FIGS. 10-14 are shematic explanatory figures illustrative of a pluralityof different embodiments of the unit(s) shown in FIG. 3.

FIGS. 15-18 are charts for showing several test results.

FIGS. 19 -20 are schematic views for showing main dimensional ratios ofthe spinning units of conventional comparative design.

Referring now to the accompanying drawings, substantially a preferredembodiment of the invention will be described in detail.

In the general arrangement view shown in FIG. 1, numeral 1 denotes aspinneret-funnel assembly of the double funnel type comprising aspinneret 2, an inner funnel 4 and an outer funnel 5, as shown mostclearly in FIG. 2 on an enlarged scale relative to that of FIG. 1. Thespinneret 2 is provided with a number of fine extrusion orifices 3',each of which has a bore diameter 1 of 0.8 mm in the case of manufactureof cuprammonium filaments by way of example. The spinning solutionsupplied by a spinning pump of the metering type, through a filter, notshown, and a feed pipe from a reservoir, all being not shown only forsimplicity, to inlet pipe 21, fitted with an on-off control cock 20 onlyshown schematically in a highly simplified way, and a reduced inletopening 22 which is keptv in fluid communication with the interior spaceof spinneret 2.

Spinneret 2, inner funnel 4 and outer funnel 5 are cocentricallyarranged with each other, the inner funnel being spaced at a verticaldistance A below the spinneret 2 when measured from the lower surface oforifice plate 3 formed with said extrusion orifices 3', to the upperextremity of the inner funnel 4. The outer funnel is arranged so that itencloses the spinneret 2 and the inner funnel 4 with an appreciable ringgap as shown. The inner funnel 4 consists of a funnel proper 4a and areduced tail pipe 4b which protrudes downwards from interior space ofouter funnel 5 through a bottom closure member 7 which is made of asealing material such as rubber or the like and closes at the mostreduced lower end of the outer funnel 5 which is fitted at its upper andmost enlarged end 5a with an inlet pipe 6 for supply of a firstcoagulation bath liquid from a certain supply reservoir by a supply pumpnot shown.

Numeral 8 denotes generally a unit for providing a liquid braking effectupon the entrained liquid by the extruded and partially coagulatedfilaments which emerge from the assembly 1 and shown by a single line at13 only for simplicity, through the way of spraying a second coagulationliquid as will be described more in detail hereinafter.

The unit 8 is shown in FIG. 3 more in detail. This unit 8 comprises aninside guide funnel 9 and an "outer boxshaped casing member 10concentrically arranged thereto and fitted with an inlet opening 11which is connected through a feed pump to a certain supply reservoir,although not shown only for simplicity. The inside guide funnel 9 isformed at its intermediated part between its upper and lower extremitieswith male threads 90 by which the casing member 10 having correspondingfemale threads 10b is fixedly attached to the guide funnel 9 and by thehelp of a nut 43. The fun nel guide 9 consists of a funnel head 90 and atail pipe 9b concentrically extending downwards therefrom and madeintegral therewith a ring hollow liquid space 10a being formed aroundthe tail pipe 9b and within the interior of said casing member 10. Thelower end of tail pipe 9b is bevelled atits outer peripheral surface asshownat 9c in FIG. 3, so as to represent a sharp ring edge at the lowerextremity of the tail pipe. The casing member 10 is formed integrallywith a depending hollow cone-shaped projection 10c which forms, in turn,in combination with the oppositely arranged bevelled surface 90 areducing ring-shaped nozzle opening 12, so as to inject a thin liquidring jet 23 towards the running bundle of parallel and continuousfilaments 13. The included angle of the thus provided ring nozzle 12 isshown at 0 in FIG. 3. This angle 0 may be about 20 150 degrees as arecommendable'value.

Below the unit 8, a lower funnel 14 is fixedly positioned at asubstantial distance from the unit 8. For

simplicity, however, fixedly positioning means of this lower funnel 14have been omitted from the drawing. This is applied to said unit 8. Thefunnel M is shaped in its cross-sectional configuration into a cup whichrepresents a bottom outlet opening shown at 14a.

Numeral I5 represents a stationally arranged guide bar which serves forguiding the filaments 13 so as to deflect their passage from thevertical to a substantially horizontally extending one for leading themto a saddle type stationary filaments guide 16. The bar !5 may be anelongated roller under occasion.

The saddle guide 16 is shown more specifically in FIG. 4 which guide ismade preferably a high wearresisting ceramic material such as sinteredtitanium oxide. This guide 16 is formed with a thin filaments passagegroove 16a on its outside surface and along its concave valley as shownand with a liquid-receiving blind hole 16b so as to receive aconventional liquid serving for the regenerating purpose as is wellknown, from a supply nozzle 24 positioned above said opening 16a at asmall distance. A plurality of this kind of saddle guides may be used ina lateral row relative to the filaments passage extending between theguides 15 and 16. i

In FIG. 5, a pair of multivane type cooperating rolls 17 and 18 areshown. These vanes are generally and commonly shown at 17a and 180,respectively, having respective shafts 44 and 45 which are rotatablysupported by antifriction bearings, not shown. These rolls l7 and 18 areserves for shake-off service for the supplied filaments, which meansthat the filaments are fed in their tensioned state and shaked off bythe action of the cooperating vanes 17a; 18a of the rolls 17 and 18 soas to occupy a slackened and complexedly looped state upon a travellingpervious endless belt 19 which may preferably be a wire net band or aperforated one, as the case may be.

Each of the vanes 17a; 18a together with their respective rolls 17 or 18is made preferably of stainless steel and fitted with a sheath 25 madeof a resilient material such as rubber, plastic material. According toour practical experiment, the provision of this resilient or elasticsheath 25 to each vane 17a or 180 has a most important role for thepurpose of the invention. The

stacked filaments on the travelling primary belt or conveyor 19 isreversed up to down as a whole and placed on a secondary perviousconveyor 27 which may be advantageously an endless wire net belt orperforated band.

Further conventional several after-treating zones 28 39 are described inthe following together with the operation of the present embodiment.

The conventional spinning solution such as for use in the cuprammoniumfilaments is fed through the pipe 21 into the spinneret 2 and extrudedfrom the extrusion orifices 3.

At the same time, the primary bath liquid, warmed water in this specificembodiment, kept at 20 60C, is supplied frominlet 6 and led to flowthrough the inside funnel 4, at a rate of 0.2 0.6 m lkg of filaments.

Other kind and rate of primary bath liquid may naturally be employed forperforming other kind of wet spinning process for different kinds fromthat specified above.

Thus, the filaments 13 are delivered from the tail end of the pipe 4b,together with the down-flowing primary bath liquid into the liquid brakeand spray unit 8 and led to the bore of the inner funnel 9. At the endof this filaments passagethrough the unit 8, the filaments are impingedupon by a thin ring film-shaped jet of secondary coagulation bath liquidwhich is again warmed water in this specific embodiment, being kept at40 C and fed at a rate of 0.3 0.8 in per kg of the filaments.

As was referred to, the included angle 0 bath of the cone-ring shapedbath liquid jet amounts generally to 20 degrees. The feed rate of thefilaments may safely amount to 400 500 in per min. or still higher.

It is very important to select the vertical component of the injectedjet is considerably smaller than the travelling velocity of the runningfilaments so that the entrained primary bath liquid is subjected at thisplate to a substantial amount of the liquid brake action exerted by thejet.

If this measure is not employed, the entrained liquid will impinge uponthe liquid pool contained in the lower funnel l4 and will disturb theliquid pool. This pool is naturally kept at a constant level in thefunnel by adopting an overflow means, not shown. A bath liquid supplymeans may also be provided for feeding it to the funnel 1 8 with thesecond bath liquid or a different one, although the inlet opening andthe like supply means have been omitted from the drawing only forsimplicity and on account of its very popular nature. When suchdisadvantageous liquid impinging action should occur, filaments breakagein this zone, or a later generation of mass fluffs may be unacceptablyincreased. This is one of the predominant main reasons which haveinhibitted a substantial increase of the spinning velocity. By employingthe above liquid brake measure, the entrained bath liquid can, to asurprising degree, invade in to the liquid pool in the lower funnel andwill assure a sufficient and even coagulation of the filaments underbeing subjected to coagulation.

The thus coagulated filaments are delivered from the bottom opening 140of the funnel 14 together with the down-flowing combined stream of theprimary and secondary bath liquids.

Although the bar 15 serving the deflecting the filaments passage and forseparating the entrained bath liquids therefrom in a physical way, wasreferred to stationary" only for convenience of the disclosure, the pinis made into a rotary or movable one and fitted with a liquid cleaningdevice for removal of deposited copper hydroxide as appeared. Thus, thewhole surface of the guide pin 15 is always kept in a clean and neatcondition. However, such rotary or the like pin-drive means, and thecleaning device serving for this purpose are highly conventional, sothat the details thereof have been omitted from the drawing.

After subjected to'deflection in the travel passage and upon physicalseparation of the entrained bath liquid(s), the filaments are conveyedto the saddle guide 16 so as to travel along the narrow passage 160 wasalready referred to hereinafter. During this passage, the filamentsformed in a bundle are brought into contact with a bath liquid which maypreferably of the same kind to the secondary one which is beingcontinuously fed from a certain supply source, not shown, through nozzle24 to the reception opening 16b. Then, the liquid gathers automaticallyto the area of filaments guide passage 16a on account of thespecifically selected saddle guide 16 and for pprforming the finalcoagulation step to the travelling filaments, although shown onlyschematically in FIG. 1, but, not shown specifically in F IG. 4.

The thus coagulated filaments 13 are led between the pair of vane typeshake-off rolls 17 and 18, thereby these filaments being subjected tovibrations so as to represent wavy forms in the space under the actionof mutually and partially engaging vanes 17a and 17b of these rolles, asshown at 13a in FIG. 5. Therefore, the filaments range 13 is kept undertension by subjecting to a considerable amount of frictional resistanceprovided by the partial engagement of these vanes, while the leadingrange 13a of the filaments is perfectly loosened. Therefore, this rollapir acts as the filaments state converter expressed in the above sense.Then, the filaments 130 are placed on the travelling pervious firstconveyor 19 in a perfectly loosened state. The rolls l7 and 18 arerotated in the opposite directions as shown by small respective arrows Pand Q, so as to, naturally feed the loosened state filaments 13a traveldownwards.

In this respect, it should be noted that when these rolls are made of arigid, hard and antichemical material such as stainless steel, thefilaments are entangled around the roll vanes, since the filaments arewet with the bath liquid(s) and liable to stick to any rigid member whenbrought into contact therewith. This disadvantageous tendency is rathermore considerably predominant in the case of fine filaments, although itis practically in a bundle as appearing in the present treating stage,than the case of a tow. By this phenomenon, filament breakages may beobserved more frequently in case of a substantially increased runningvelocity of the filaments. When even a single filament is stuck around avane and brought into rotation with one of the treating roll 17 or 18,other remaining filaments are pulled up together as in the manner when aperson pulls by his fingers end part of a spider's web. Thus, when thisshould occur, the whole operation of the processing plant could beconsiderably injured. Under extreme occasion, the plant must be stoppedfor necessary readjustment.

It has been observed, however, that there are such two groups ofmaterials for the vanes, when observed the rotating movement of theshake-off rolls in combination of the filaments bundle and through ahigh speed cinematograph, that one group of them can not drive off theentrained liquid through the centrifugal action, while, with the othergroup of materials, an efficient centrifugingly liquid-separating actioncan be assured. The first group comprises steel or the like metallicmaterial, while-the second group comprises semi-soft and elasticmaterials such as rubber, plastics and the like. Based upon ourexperimental knowledge of the above facts, we have employed elasticsheath 25 fitted on each of the vanes 17a and 18a. When the vanes aremade of a semisoft elastic material such as rubber, it has been observedthat droplets are continuously and effectively driven off from the outeredge of each vane under the influence of the rotating rolls at a highspeed,

- arrow. B and substantially in a thick and loose layer or sheet, thethickness of which can be adjusted by modifying the travelling speed ofthe primary conveyor 19 which can be referred to a filaments positionconversion means. In parallel to the lower travelling layer (see arrowB) and at a small gap distance therefrom, there is a larger andelongated conveyer 27 travelling in the direction C which is the sameone as that shown B. This conveyor is denoted main or secondary con- 13aformed on the primary conveyor for fixing its loosened texture bysupplying a proper amount of divided liquid thereamong.

As seen from FIG. I, the secondary conveyor 27 covers sufficiently thewhole travel range of the primary conveyor, and the loosely texturedfilament layer or sheet 13a is transferred as a whole and in anundisturbed manner onto the upper travelling layer of the secondaryconveyor 27 and thus conveyed through a series of after-treating zones41 and 42.

The zone 41 consisting of a travelling endless wire net band shown in ahighly simplified way and contains a conventional acid-treating section28; a cold water washing section 29, a hot water treating section 30; ade-watering section 31, and an oiling section 32 and a de-oiling section33. Within this zone 41, there are provided two pairs of guide rollers31 and 35 for guiding the conveyor 27 in a suitable way.

A similar endless conveyor 42 defines a further zone which contains atunnel dryer section 34 and a humidifier section 35. A takeup positioncontrol section 36 (which may be of the photo cell system although notshown) is provided after the section 35.

Further, warping sections 37 and 38 are also provided for effecting windup of the thus properly oriented or warped filaments by a winder 40through a lubricating and bundling section. in the elevational view,only a single line represents a loose textured mat-like sheet 13b whichcontains, however, a large number of, for instance 300, bundles ofmultifilaments supplied from a corresponding number of spinning andcoagulating units, each comprising main constituents 1, 8, 14, and 18. I

The endless band 41 constitutes a kind of scouring cover net or clothand the next endless band 42 constitutes a kind of drier cover net orcloth. These cover nets efficiently press by their lower side travellinglayers the loosely textured mat-like filaments layer 13b positioned onthe secondary conveyor 27 at respective zones 41 and 42 for protectingthe layer against otherwise possible disturbances by pouring severaldifferent scouring liquids and air-agitating effects by the action ofdrier fans, not shown.

it will be seen from the foregoing that the filaments are extruded,coagulated and then after-treated in succession until they will havebeen wound up into cones, cheeses or the like commercializable form,continuously even at a high spinning and processing speed such as 500 mper min. or even still faster.

EXAMPLE 1 8, the including cone angle 0 of the jet amounted to 60 1ating appreciable impinge. Liquid was separated from the filaments bycontact with the movable type deflector pin 15.

A clip treatment was made for the filaments by use of an aqueous, 10%sulfuric acid solution on the saddle guide and led to pass between thepair of vane-type shake-off rolls.- Sheaths were of natural rubber ofhardness 60 degrees. Roller revolutions were 397 r.p.m. By use of thesevane type shake-off rollers, total 15,000 hours of operation could beeffectively and continuously performed without appreciable generation offilaments breakage and/or mass fluffs, when counted on total spinningunits.

The thus shaped-off and position-converted and placed on the secondaryconveyor 27 were processed as before and finally wound up into cheeses.The filament properties were not changed in any appreciable way. Testresults showed:

Dry strength: 2.0 g/d; dry elongation rate: 1 1.5%; wet strength: 1.4g/d; wet elongation rate: 18.5%; generation rate of mass fluffs: 0.5 per10 m, which means a rather favorable result relative to those ofconventionally prepared cuprammoniurn rayon filaments.

When increasing the spinning velocity, as high as 500 1,000 in per min.,it has been found that the distance L, (see, FIG. 7) as measured fromthe lower end of the miner funnel 4 and the uppermost part of thecombined hydraulic brake and secondary bath liquid spray unit 8, and theconditions of the primary bath liquid conditions such as feed rate andtemperature thereof, for minimizing the number of filament breakage andthe generating rate of mass fluffs to respective minimum value.

On the other hand, the length L, (see, FIG. 7) as measured between thelowermost part of the unit 8 and the positioning level where the movabledeflector pin 15 (see, FIG. 1), as well as the conditions such as feedrate and temperature of the secondary coagulating bath liquid.

The first combination of L, and the like said above influencessubstantially upon the spinnability of the filaments, while the secondcombination of L and the like said above influences substantially uponthe coagulation properties of the filaments. The ratio: 1 /1, mustpreferably be chosen to l-5, l and I, being shown in FIG. 7. On theother hand, d, must preferably be equal to (l/2 l/ d,, d, and :1, beingshown in FIG. 8.

In the related upper zone of the spinning unit, having relationship withthese dimensional data d,, d,, l, and 1,, when employing theabove-mentioned relative dimensional requirements, the coagulation ofthe filaments can be suppressed to a minimum degree, and it is better touse the spinning solution for uniformly stretching the extrudedfilaments. Therefore, and additionally considering the economy of theoperational cost of the manufacturing plant, the feed rate of theprimary coagulationbath must preferably reduced to a possible minimumand the operating temperature thereof must preferably be a possiblelowest value.

When it is intended to carry out the coagulation 'of the filamentswithin the sphere of the said spinning zone to an appreciable degree,the operating temperature of the primary bath liquid must be increasedto a certain appreciable level, leading definitely to generate thefouling deposits on the inside wall surface of the tail pipe of theinner funnel by the separated compounds from the filaments. Should thisoccur a continuous and effective spinning operation could besubstantially distrubed, and under extreme conditions, the spinning maybe brought into a dead stop, when the operational period has elapsed fora considerably long time. Additionally, uneven stretch effects may beinvited among the filaments under manufacture.

Although the operating conditions to maintained within the inner funnelmay vary with occasionally employed spinning velocity, compsotion of thespinning solution, total and filament denier and the like data, thefohlowing ranges of operating factors may preferably be adopted in thecase of spinning of cupranimonium filaments at a spinning velocity of500 1,000 m per min.

d 50 mm; l,=40- 300 mm;

d,= 3 25 mm; I 40 1,500 mm;

feed rate of primary coagulant: 300 3,000 c.c. per

operating temperature thereof: 60C.

It is naturally desirous and recommendable to substantially terminatethe coagulation when the filaments has travelled along the distance LAlthough the operating conditions for attaining this requirement willnaturally vary with occasional spinning velocity, composition of thespinning solution, aimed total and filament denier, conditions in theinner funnel and the length L, in the above sense, the recommendabledata for spinning cuprammonium filaments at a spinning velocity of 5001,000 m per min. may

, preferably be:

temperature of secondary bath liquid: 4095C feed rate thereof: 300-3,000c.c. per min.

The bore diameter d, of funnel 9 must be so choosen that the filamentscan not be brought into contract with the bore wall surface duringpassage of the filaments therethrough. As the second requirement for thehydraulic unit 8, the ring cone jet must be directed towards thedownwardly travelling filaments group as a center. By adopting thishydraulic braking measure, the downward travel speed of the filamentscan be damped to an appreciable way. For this purpose, the angle 0 mustbe selected preferably to 20 150 degrees, as was referred to. As for theliquid jet velocity of secondary coagulant for attaining the abovepurpose, the recommendable condition relative to the spinning velocitywas referred to hereinbefore.

In FIGS. 10 14, several embodiments of concentric arrangement of one ormore jet streams by use ofa single or a plurality ofjet injectors areshown. A glance at these figures, the design and operational modes ofthe jetting means can easily be understood without any further analysisthereof.

Relationship between the ammonia-removal rate, or spinnability in termsof critical spinning velocity, and the length L, is shown in FIG. l5.

l0 Relation between these characteristic values and the length L, isshown in FIG. 16.

In FIG. 17, relationship between spinning filament tension and L isshown. Relationship between spinning filament tension and L is shown inFIG. 18.

15 As seen from the foregoing experimental data shown in FIGS. 15 18,the data L and L, influence considerably upon the spinnability andcoagulability of the wetspin and coagulated filaments. In order toincrease the spinning velocity, the length L, must preferably increasedwhen saying in the general sense. On the contrary, for increase ofcoagulability, the length L; must be increased correspondingly.

In order to avoid a sudden coagulation of the filaments, two or morebraking injectors may be arranged in series to each other along thetravel passage of the filaments for allowing to inject different brakingjets in two or more stages and under differently adopted injectingconditions.

From the data shown in FIGS. 17 and 18, it will be seen that byselecting proper values of L, and L a hitherto impracticably increasedhigh speed spinning at 500 m per min. orstill higher can be realizedwith such results'as with a higher ammonia-removal rate than 80% and ata green filament tension 20 g or still lower.

COMPARATIVE EXAMPLE A conventionally prepared cuprammonium cellulose 40spinning solution having a composition of: cellulose content 10 wt.ammonia content 7.2 wt. and copper content 3.6 wt. were wet spun bymeans of conventional comparative spinning units as shown in FIGS. 19and 20 and compared the results with those obtained according to thisinvention. The comparative results are shown in Table 1( A) and Table1(B) which is a table to be jointedtogether.

TABLE 1(A) Kind of spinning process Conventional Japancsc patentpublication Inventive N0. ll5/lJ5G U.S.I. 3,019,755

Spinning velocity 500 600 700 $00 40 (It) 100 100 150 Spinningconditions and filaments characteristics:

h (mm) m0 m0 100 too 100 400 400 120 1 0 12 (mm) 300 300 300 300 150 110la 111.) 70 70 70 130 I50 I30 130 14 (mm. 200 00 1 m-) 800 800 800 800I50 240 400 400 L2 (mm) 400 400 600 000 Spinning conditions: Primarybath temp. C.) 40- 45 45 4o 15 35 33 lilo Supply rate thereof (co/min.)1,100 1, 200 1,500 309 3 0 Secondary bath temp. C.) 80 4o 0 Supply ratethereof (co/min.) 1,100 1,500 2,000 300 300 TABLE 1(B) Kind of spinningprocess Conventional Japanese patent publication Inventive No. 115/1956U.S.P. 3,049,755

Spinning velocity 500 600 700 800 40 60 100 100 Spinning conditions andfilaments characteristics:

Filament tension 1) 8. O 12. 0 15.0 18. 0 11. 0 13.0 16. 0 8.0 8. IAmmonium removal rate (percent). 85 Si 8-1 85 5 S0 78 8'3 80 Filamentscharacteristics:

Dry strength (g./d.) 2. l 2. 1 2. 2 2. 0 1.3 2. 0 2. 0 L 1 1. 9 Dryelongation rate 11. 8 10. 3 11. 4 i1. 3 14. 0 12. 5 12. 0 11. 7 it. 5Wet strength (g./d.) 1. 1 1. 2 1. 0 1.1 1. 4 1. 3 1. l 1. L l. 1 Wetelongation rate (percent) 18. 7 17. 5 15. 3 13. 4 1.3.0 18. 0 17. 0 17.0 11. 0

As may be ascertained from these experimental results, the properties ofthe filaments prepared according to the inventive teachings, althoughthe spinning velocity was selected to an amazingly high value rangingfrom 500 to 800 in per min., a coagulability which is comparative to theconventional value could be realized. Strength and elongation rate werealso similar to those conventionally obtained. Fluff formation rateamounted to very favorable values.

Various changes and modifications can bemade within spirit of dependedclaims. For instance, it should be noted that each of the said sheath 25may be replaced a coated layer of elastomer as a modification in FIG. 6.

1. An apparatus for use in a continuous wet spinning process comprisinga pair of oppositely rotating rollers adapted to receive the travellingfilament therebetween, each of said rollers being provided with aplurality of radially extending vanes having an elestomeric coatingthereon, said rollers being spaced such that the vanes of the rollersare disposEd in partial overlapping engagement with each other wherebythe filaments will be vibrated to accelerate the centrifugal drive-offof water entrained by the filaments in the form of fine droplets.